Rotary drum brake assemblies are well known in the art of braking motor vehicle wheels. Such assemblies characteristically include a stationary backing or torque plate secured to the end of the axle and about which rotates a rotary drum to which the wheel is secured. The brake assembly features a pair of opposed brake shoe assemblies that are respectively pivotally mounted at one end to the backing plate within the drum and carry frictional braking material facing theretowards. Upon application of the brakes, a mechanism such as a rotary or a wedge cam disposed between the opposite end of the brake shoe assemblies, is caused to rotate or to be axially displaced and spread the brake shoe assemblies apart for a distance sufficient to enable the braking material to frictionally engage the drum for the braking thereof.
At least one and often two or more resilient biasing members such as coiled springs (usually called "return springs") are employed to resiliently urge the brake shoe assemblies towards each other for a distance sufficient to disengage the frictional braking material from the drum upon release of the brake.
Examples of rotary drum brake assemblies and the various means employed to secure the biasing members so that they operate in the manner described above are disclosed in U.S. Pat. Nos. 2,064,103; 2,751,048; 2,788,866; 3,837,446; 4,064,978 and 4,216,850, the disclosures of all of which are incorporated herein by reference.
All of the above disclosed brake shoe assemblies that are secured directly between both of the brake shoe assemblies or are otherwise unable to be disposed in close proximity to the cam so as to increase the mechanical advantage obtained thereby for pivoting the brake shoe assemblies towards each other upon release of the brake. The anchor bracket of the present invention not only provides additional clearance for steer hubs but also eliminates the practice of heretofor having to trim off the tip of the rotary cam in order to obtain return spring clearance which has the adverse effect of reducing cam reserve i.e. the amount of extra rise in the cam operable to prevent the cam from flipping over when the brake shoe assemblies are spread by the cam to the maximum separation distance between them.